This application makes reference to and claims all benefits accruing under 35 U.S.C. Section 119 from an application entitled, xe2x80x9cMethod for Formatting Facet of Optical Waveguide Elementxe2x80x9d, filed with the Korean Industrial Property Office on Dec. 24, 1999 and there duly assigned Serial No. 99-61597.
1. Field of the Invention
The present invention relates to an optical waveguide element, and more particularly to a method for formatting the facets of an optical waveguide element for use with optical communication.
2. Description of the Related Art
In general, the entire process of manufacturing an optical waveguide element comprises the following steps: forming an optical waveguide element including a core layer and a cladding layer by laminating film on the upper substrates of the layers; dicing to cut the optical waveguide element in an appropriate length for packaging; and, formatting the facets of the optical waveguide for use with optical communication.
Since the facet-formatting process is required to enhance the efficiency of combining the optical waveguide element and optical fiber, the expense and time incurred for the facet-formatting operation are a considerably important part of an optical fabrication process. One of the methods used in the conventional facet-formatting process is directed to the fine processing of an object under low pressure by rubbing the object to a desired form. The facet-formatting process employs an abrasive method for rubbing the facet of an optical waveguide element on a sand paper or other alternative abrasive materials. Polishing and lapping are some of the abrasive methods. The lapping technique incorporates a lap, which is a rotatable disc consisting of a soft material, such as cast iron, copper, or wood, to polish the subject element by moving the lap device against the subject element, while introducing a lapping material, which is an abrasive liquid, between the lap device and the subject element. There are different degrees of hardness used for the lapping materials, which is listed in the following order: diamond; SiC, Al2O3, etc.
FIG. 1 is a perspective view of the conventional polymer optical-waveguide element with the auxiliary blocks mounted thereto. FIG. 1 shows the substrate layer 11 composed of a material, such as silicon, glass or melted silica, and the core layer 12 and a cladding layer 13 laminated on the upper portion of the substrate layer 11. Two auxiliary blocks 14 are fixed onto both ends of the upper portion of the cladding layer 13 through the adhesive coupling 15. The auxiliary blocks 14 are positioned at both ends of the polymer optical waveguide element 16. The function of auxiliary blocks 14 is to protect the film of the polymer optical waveguide 16 when the optical waveguide element 16 is attached to an instrument, such as a jig, etc., during the abrasion operation. The auxiliary blocks 14 serve to enhance the adhesivity of the polymer optical waveguide element 16 to other elements adhered thereto by widening the adhering area.
FIG. 2 is a side view illustrating the facets of the polymer optical waveguide element 16 and the auxiliary blocks 14 shown in FIG. 1. The polymer optical waveguide element 16 and the auxiliary blocks 14 have two ends of facets for adhering to optical fibers or other optical elements. FIG. 2 is a simplified block diagram showing one side of the facets. On the surface of the facet, the portion requiring fine optical processing is near the core region 12 and the cladding layer region. The reason is because an optical signal is inputted to or outputted from the polymer optical waveguide element 16 along the core layer 12. The cladding layer 13 allows the optical signal transmission to travel within the core layer 12. The substrate 11 and the auxiliary blocks 14 have no functional structure for the transmission of the optical signal.
FIG. 3 is a diagram showing the conventional method of formatting the facets of the polymer optical waveguide element 16 shown in FIG. 1. The auxiliary blocks 14 and the polymer optical waveguide element 16 are fixed onto an instrument, i.e., a jig and other alternative holding devices, for polishing one of the facets. One end of the facet is in contact with the upper surface of the plain abrasive material 17. Here, a predetermined pressure is pushed downward at the opposite facet of the one being polished so that the contact surface between the polymer optical waveguide element 16 and the abrasive material 17 can be tightened. Such pressure in a vertical direction is maintained during the abrasive processing. During the abrasion process, the abrasive liquid 18 is introduced between one end of the polymer optical waveguide element 16 and the surface of the abrasive material 17. The abrasive liquid 18 consist of micro-size particles, such as Al2O3. Thus, the level of the abrasive processing of the facet is controlled by varying the size of particles contained in the abrasive liquid 18. Accordingly, an abrasive liquid 18 having a particle size of several decimal um is used at the beginning of the abrasive processing, while an abrasive liquid 18 having a particle size of several xcexcm is used in the middle of the abrasive processing, and an abrasive liquid 18 having a particle size less than 1 xcexcm is used toward the end. The problem posed by this kind of facet processing method is time-consuming processing due to the abrasion of changing the abrasive liquid 18 in each step.
It is, therefore, an object of the present invention to provide a method for formatting the facets of an optical waveguide element capable of reducing the processing time in the prior art system.
To achieve the above and other objects of the present invention, there is provided a method for formatting the facets of an optical waveguide element including a core laminated on the upper surface of a substrate layer and a cladding layer, comprising the steps of: (1) attaching auxiliary blocks on the top of the optical waveguide element so that the auxiliary blocks are protruding from both ends of the optical waveguide element and coated with the adhesive from a bottom of the protruded auxiliary blocks to the facets of the core and cladding layers of the optical waveguide element; (2) contacting the auxiliary blocks with a thermal plate, which has undergone an optical facial treatment, so that the facets of the optical waveguide element including the auxiliary blocks formed in the first step can make a predetermined angle in an inclined relationship to a direction of a normal to the thermal plate; (3) applying a pressure on the optical waveguide element including the auxiliary blocks in a direction normal to the thermal plate until the adhesive coated on the facets of the optical waveguide element is completely melted; (4) of moving the optical waveguide element including the auxiliary blocks in a direction horizontal to the thermal plate at the moment when the adhesive coated on the facets of the optical waveguide element including the auxiliary blocks is completely melted; and, (5) removing the optical waveguide element including the auxiliary blocks away from the thermal plate at the moment when the adhesive coated on the facets of the optical waveguide element including the auxiliary blocks is completely removed.